CHARLOTTE, N.C., and WASHINGTON-On a recent sunny Saturday morning, dozens of runners in brightly colored shorts and numbered race bibs crossed the finish line during an early morning 5-K near uptown Charlotte, N.C. The festive scene of live music and free snacks offered a stark contrast to a public hearing unfolding in a classroom at the adjacent community college: In a windowless room with fluorescent lights, 34 gray chairs neatly lined the gray walls and gray carpet, and less than 10 local citizens gathered for a public hearing scheduled to last as long as three hours. The topic: congressional redistricting.

But while the turnout was small and the setting was dull, the implications are huge: The way state legislators here-and in states across the country-redraw district boundaries in response to the 2010 Census could shape political power for at least a decade. For Republicans in North Carolina-one of the most gerrymandered states in the country, where the GOP now controls the state legislature for the first time in nearly a century-playing fair could be one of the biggest challenges of their careers. North Carolina legislators will likely unveil proposed maps within the next month.

"This is the best position the GOP has been in in the modern era of redistricting," said Tim Storey, an expert on redistricting at the National Conference of State Legislatures. Republicans hold 26 state legislatures, the most since 1952, when they also held 26. The change in power is particularly striking in the South: In 1990, Republicans didn't control a single Southern chamber, but now they control both chambers of nine state legislatures.

North Carolina is grabbing national attention because of its burgeoning population and its changing political makeup. The state population grew by 18.5 percent in the last decade, and the number of unaffiliated voters has grown from 6 percent in 1990 to 24 percent now. "North Carolina is a very competitive and volatile state politically right now," said John Rustin, an expert on redistricting at the North Carolina FreeEnterprise Foundation, a pro-business think tank. "We're the consummate swing state."

The handful of citizens signed up to speak at the April 30 hearing seemed to understand the implications, and they all had a similar plea for the four members of the redistricting committee on-site: Draw the lines fairly. Seven out of the 11 speakers (including those at three satellite locations via videoconference) asked legislators to protect minority voters during the redistricting process. At least four had another concern: Keeping communities together instead of gerrymandering for political advantage-the kind of tactic Democrats have notoriously leveraged in the state for decades. Now voters can hold legislators more accountable to these demands: Since the last Census, the iPhone was invented, and Texas, for one, has created a mobile application for smartphones, so voters can check proposed maps for where they live. Florida voters can even draw their own maps in an online application and submit them to the legislature.

From a satellite location, one North Carolina speaker described his 12th district home as "an extreme gerrymandering district." The 12th district, which Democrat Mel Watts represents, lies like a piece of spaghetti across the middle of the state, connecting disparate black communities so they make up 45 percent of voters. The district's borders have received Supreme Court scrutiny numerous times. "I would rather that districts are drawn up as communities in localized areas instead of making what is the equivalent to a snake in the middle of the state just so that you can get a voting bloc for one source of representation," the speaker told legislators.

In 1993, the Supreme Court echoed that concern in the case Shaw v. Reno, which addressed North Carolina's districts. "A reapportionment plan that includes in one district individuals who belong to the same race, but who are otherwise widely separated by geographical and political boundaries, and who may have little in common with one another but the color of their skin, bears an uncomfortable resemblance to political apartheid," wrote Justice Sandra Day O'Connor in the majority opinion.

In North Carolina, as in the rest of the country, the population is draining from rural areas and moving to cities-which could have the benefit of creating more geographically compact districts. "In the past they were slicing and dicing certain counties to make sure that certain people won elections-and more importantly-that certain parties won elections," said Sen. Bob Rucho, the Republican chairing the Senate redistricting committee, in an interview. "My town of Matthews is split in the middle. But that's a community of interest. Why was it ever divided?" Indeed, for mapping purposes, what is a "community"? John Hood, the president of the John Locke Foundation in North Carolina and an expert on redistricting, said it must be defined by close geography, keeping a district as compact as possible so people living in the same place are represented together.

"When you get into 'communities of interest' language, you start getting into weird territory," said Hood. "It could be the town of Apex. It could be people who work in manufacturing. It could be people who share the same religion. . . . It gets into an area where I don't think we want a legal standard applied."

Beth Henry, a retired Charlotte attorney, told the committee she's a Democrat who sometimes supports Republican candidates, and she worries about drawing lines that make some candidates sure winners. Does Henry think the GOP will handle redistricting fairly? "I'm sure they will be tempted-just like obviously in the past the Democrats have used gerrymandering to their benefit," she said. "So it's understandable that that's a big temptation."

North Carolina voters aren't confident Republicans will resist the temptation: A recent poll from the nonpartisan North Carolina Center for Voter Education found that 76 percent of voters from both parties believe that legislators have a conflict of interest in drawing districts themselves. For the last decade, various Republican legislators in North Carolina have introduced measures to reform redistricting, like creating a nonpartisan commission to draw the maps or setting up stricter rules for map drawing. State Democrats, now that they're out of power, are interested in these ideas, but Republicans say there isn't time to pass new redistricting laws and create new maps in time for the next round of primaries.

The 2010 election, so big for Republicans, gave some evidence of gerrymandering in North Carolina. While Republicans won control of both chambers of the legislature for the first time since Reconstruction, the party only took one congressional seat, which some experts say indicates how gerrymandered congressional districts are in Democrats' favor. Map scrutinizers expect that in a wave election, there should be a "uniform swing" in terms of wins for a party.

"We've never been in charge before. It's going to be different this time," promised Sen. Rucho, who chairs the Senate redistricting committee. Even if it's to your disadvantage? "I'm going to follow the law." Other Republican legislators in North Carolina have promised that they will not gerrymander, whatever that means in practice. There's no firm legal standard for gerry­mandering at the congressional district level, beyond one simple guideline from the Supreme Court: one person, one vote. Each district must have an even population, within a small percentage of variation. In a 2004 case that went to the high court, Georgia had packed Republican districts with more people than Democratic districts, so Democratic voters had more power at the polls than Republicans. The justices ordered a more even distribution of the population.

North Carolina isn't gaining a seat, despite its surge in population, but several congressional districts could change enough to make them more competitive for Republicans, like the currently Democratic 13th District near Raleigh. The state has two districts in which minorities are in the majority, and Hood said Republicans may try to create a third (the state's Hispanic population grew by 111 percent in the last decade). But creating a third minority district, Hood said, would be a "roll of the dice," in terms of unpredictable political and legal fallout.

Southern states' redistricting maps, including North Carolina's, are generally governed by the Voting Rights Act, which is designed to protect minorities' voting rights and subjects new electoral maps to Justice Department approval. Republicans and Democrats tend to interpret the act differently, Hood explained. Republicans believe that if legislators can draw a district that gives African-Americans a majority, for example, legislators should do that. That, in turn, theoretically creates more Republican-friendly districts elsewhere. Democrats believe that it's sufficient to draw districts with a "substantial minority," Hood said, spreading out the minority population in order to make more districts competitive for Democrats.

Twenty years ago, the NAACP supported Republicans' interpretation of the VRA, pushing for majority-black districts instead of spreading the black population out to elect more Democrats. But the organization's position has changed: "They've sort of decided the Democratic Party's fortunes are more important," Hood said. The Justice Department, which will need to approve North Carolina's redistricting plans, tends to side with Democrats' interpretation of the VRA, Hood says. But, he added, "The VRA jurisdiction is just muddy enough to give both sides a rationale for their position."

The potential legal challenges have cast anxiety over the whole process. Rep. Ruth Samuelson, a Republican from the Charlotte area, is vice-chair of the House redistricting commission, but she declined an interview out of an abundance of caution for the potential legal challenges to the maps. Rustin noticed this level of caution in the legislative hearings he attended too: Legislators didn't make off-the-cuff remarks, but read from written statements, and a stenographer was present.